Quality of Evidence
High: Further research very unlikely to change confidence in the estimate of effect.
Moderate: Further research likely to have an important impact on confidence in the estimate of effect and may change the estimate.
Low: Further research very likely to have an important impact on confidence in the estimate of effect and likely to change the estimate.
Very Low: Estimate of the effect very uncertain.
Grades of Recommendations
Strong: Desirable effects clearly outweigh undesirable effects or clearly do not.
Weak: When tradeoffs are less certain, either because of low quality evidence or because evidence suggests desirable and undesirable effects are closely balanced, weak recommendations become mandatory.